The amount of data transferred between electronic devices has grown tremendously the last several years. Large amounts of audio, streaming video, text, and other types of data content are now regularly transferred among desktop and portable computers, media devices, handheld media devices, displays, storage devices, and other types of electronic devices.
Power may be transferred with this data, or power may be transferred separately. Power and data may be conveyed over cable assemblies. Cable assemblies may include a cable that may have wire conductors, fiber optic cables, or some combination of these or other conductors. Cable assemblies may include a connector insert at each end of the cable, though other cable assemblies may be connected or tethered to an electronic device in a dedicated manner. The connector inserts of the cable assemblies may be inserted into receptacles in communicating electronic devices to form power and data pathways between them.
When a device is disconnected, a connector receptacle in the device may be exposed to the local environment. At other times, a cable insert at a first end of a cable may be inserted into the connector receptacle and a cable insert at a second end of a cable may be exposed to the local environment. Also, when a device has a tethered cable, the far end of the tethered cable may be similarly exposed. For example, the connector receptacle or insert may be exposed to liquid or moisture. Liquid may be spilled directly on contacts of a connector receptacle or connector insert. An end of a cable may be set down in a pool or puddle or liquid. Moisture may accumulate on a connector receptacle or connector insert in a high-humidity environment. A connector receptacle or connector insert may be moved from a warm location to a cooler one. This temperature change may cause humidity in the environment to condense, and the resulting moisture to accumulate on the contacts in the connector receptacle or connector insert.
This liquid or moisture may cause the growth of dendrites between two or more contacts in the presence of an electric field. Specifically, where an electric field exists between two or more contacts, dendrites may grow between the two contacts. This growth may reduce an impedance between the two contacts. When the two contacts include one of the connection detection contacts in a USB-Type-C™ connector, an electronic device connected to, or housing, the connector may erroneously detect a connection to a second electronic device where no such connection exists. This erroneous detection of a connection may result immediately from the low resistance effect of the liquid or moisture, or may be delayed for a period of time until the growth of a dendrite has proceeded sufficiently to lower the resistance to a point where such an erroneous detection may occur. When such an erroneous detection of a connection occurs, then the system may enable power or signaling on other contacts in the connector, resulting in further dendritic growth on these other contacts. Initially, the dendrites are incomplete and/or fragile, and likely to be dislodged by physical use of the connector. However, after sufficient dendritic growth, permanent functional failure of the connector can result.
Thus, what is needed are methods, structures, and apparatus that limit the amount of dendritic growth between contacts in order to avoid permanent functional failure of the connector.